abc's john schriffen is inside arrowhead stadium where today's game will still be played. >> reporter: dan, good morning. this morning, we're learning more about what may have happened in the hours leading up to this tragedy. according to the kansas city star, it all started 1:00 saturday morning when belcher's girlfriend got home late from a concert that she attended with friends. well, tragically, it ended seven hours later. when belcher shot her several times, and he then drove to the chiefs stadium where he then took his own life. this morning, investigators are trying to figure out why nfl linebacker jovan belcher killed his 22-year-old girlfriend and then took his own life. >> we heard that they had been arguing in the past. as far as recently, they had been arguing before the shooting occurred. >> reporter: police say saturday morning he shot and killed kasandra perkins, the mother of his 3-month-old daughter at their home. police say belcher's own mother was in the house, saw the murder and called 911. he then jumped in his car and drove to arrowhead stadium to the team's prac